With the recent availability of an immunoassay that measures the more stable ADH precursor peptide CT-ProVasopressin , we sought to investigate whether increased ADH levels would explain hyponatremia found in Legionella patients. We measured CT-ProVasopressin and sodium levels in a prospective cohort of pneumonia patients from a previous multicenter study with 31 patients having positive antigen tests for Legionella pneumophilia. We calculated Spearman rank correlations and multivariate regression models.
We found no evidence that increased ADH secretion would explain low sodium levels in Legionella patients, or other pneumonia patients, challenging the common believe of Legionella causing SIADH. Rather, ADH precursors were upregulated as a response to severe disease.
Future studies continuing to explore the cause of sodium disturbance in Legionella are warranted. National Center for Biotechnology Information , U.
These hormones may contribute to low sodium levels via increased natriuresis. The strengths of our study are the systematic assessment of sodium and CT-ProVasopressin in a large prospective study of patients with CAP of different etiologies.
Yet, this study also has limitations. First, we did not measure mature ADH directly. However, clinical evidence suggests that CT-ProVasopressin is a good surrogate for ADH, and may thus be used instead in clinical routine [ 55 ]. Second, we were not able to assess sodium and osmolarity measurements in urine limiting our model to the measurement of CT-ProVasopressin and correlating blood sodium levels.
Our observations were rather on the population level and not on a patient level [ 16 , 37 , 56 ]. Last, there may have been unmeasured confounders in our study population such as the use of diuretics and aldosterone antagonist, which were not recorded. Rather, ADH was upregulated in response to the stress of severe infection, which seemed to have overruled the osmoregulatory stimulus.
As a consequence, free water restriction should not be pursued in this patient population, but rather replacement of salt losses by hydration and salt repletion. No commercial sponsor had any involvement in design and conduct of this study, namely collection, management, analysis, and interpretation of the data; and preparation, decision to submit, review, or approval of the manuscript. BM has served as a consultant and received research support. All other authors declare that they have no competing interests.
All authors amended and commented on the manuscript and approved the final version. PS is the guarantor of the paper, taking responsibility for the integrity of the work as a whole, from incepton to published article. We are grateful to all local physicians, the nursing staff and patients who participated in this study.
Perruchoud, S. Harbarth and A. Conen, MD, M. Wieland, RN, C. Nusbaumer, MD, C. Bruehlhardt, RN, R. Luginbuehl, RN, A. Huber, MD, B. Walz, RN, and M. Zueger, MD. National Center for Biotechnology Information , U. BMC Infect Dis. Published online Dec Author information Article notes Copyright and License information Disclaimer. Corresponding author. Philipp Schuetz: moc. Received May 21; Accepted Dec 9. This article has been cited by other articles in PMC. Methods We measured CT-ProVasopressin and sodium levels in a prospective cohort of pneumonia patients from a previous multicentre study with 27 patients having positive antigen tests for Legionella pneumophila.
Background Low sodium levels are a common feature of patients with community-acquired pneumonia CAP , particularly if caused by Legionella pneumophila [ 1 - 4 ]. Methods Setting and population studied The present study used data from patients from a cohort of patients with radiologically confirmed CAP, who had a sodium level measured on admission and a left over blood sample for later measurement of CT-ProVasopressin levels.
Definitions In all CAP patients, the protocol specified to perform a qualitative immunochromatographic antigen test for Legionella pneumophila serogroup 1 on urine samples on admission BinaxNow Legionella; Binax.
Clinical examination and laboratory data In all patients on admission, a thorough clinical examination was performed and two prognostic scores Pneumonia Severity Index PSI and the CURB were calculated [ 27 , 28 ].
Statistical analysis Discrete variables are expressed as counts percentage and continuous variables as medians and interquartile ranges IQR or means and standard deviations SD. Open in a separate window. Figure 1. Figure 2.
Figure 3. Acknowledgements We are grateful to all local physicians, the nursing staff and patients who participated in this study. References Cunha BA. The clinical diagnosis of Legionnaires' disease: the diagnostic value of combining non-specific laboratory tests.
J Infect. An update on Legionella. Curr Opin Infect Dis. Clinical predictors for Legionella in patients presenting with community-acquired pneumonia to the emergency department. BMC Pulm Med. Sporadic and epidemic community legionellosis: two faces of the same illness.
Eur Respir J. Altered water metabolism in tuberculosis: role of vasopressin. Am J Med. Resetting of the Vasopressin Osmostat during infectios Pneumonia. Hyponatremia and inflammation: the emerging role of interleukin-6 in osmoregulation. Nephron Physiol. Perfluorocarbon-associated gas exchange partial liquid ventilation in respiratory distress syndrome: a prospective, randomized, controlled study.
Crit Care Med. Interstitial nephritis in a patient with Legionnaires' disease. Postgrad Med. Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med. Treatment of symptomatic hyponatremia and its relation to brain damage.
A prospective study. Postoperative hyponatremic encephalopathy in menstruant women. The legionaries drew their iron swords, donned their silver helmets, and jumped off the ship to burn the town to coal : legionellosis , iron buffered medium, silver stain, history of cruise ship travel, char coal yeast extract agar.
In any case of atypical pneumonia , antibiotic treatment needs to cover Legionella. References: [5]. Expand all sections Register Log in. Trusted medical expertise in seconds. Find answers fast with the high-powered search feature and clinical tools. Try free for 5 days Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer. Summary Legionellosis is an infection caused by Legionella pneumophila , a gram-negative rod that thrives in warm aqueous environments such as drinking-water systems, hot tubs, and air-conditioning units.
Epidemiology Frequency : : occurs rarely in infants , almost solely in adults of any age and typically in outbreaks High-risk groups [1] [2] Elderly individuals Individuals with chronic diseases e. Path of infection Inhalation of contaminated aerosols Cold and hot water systems ; e.
Locations at particular risk of outbreak Nursing homes Hospitals Confined travel accommodations e. Pontiac fever Incubation period : 1—3 days Mild, self-limiting course of legionellosis without pneumonia. Flu-like symptoms e. Laboratory findings Blood Hyponatremia serum sodium and hypophosphatemia are common.
Aminotransferases and creatinine may be elevated. Possible thrombocytopenia and leukocytosis Urine Legionella urinary antigen test : most important diagnostic tool ; rapid test, but only detects serogroup 1 [7] Hematuria and proteinuria are common.
Visualization of Legionella requires silver stain. Legionella culture: slow ; requires buffered iron and cysteine charcoal yeast extract agar results after 3—5 days [8] PCR : high sensitivity, high specificity [7] Serology : : A four-fold rise in antibody titer confirms legionellosis. However, the antibody titers have low specificity and sensitivity , and seroconversion can take up to 12 weeks.
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